The present invention relates to a power plug locking device that locks a power plug to an object, such as a vehicle, and prevents unauthorized removal of the power plug from the object.
Over these recent years, consumers have become conscious of environmental problems. Thus, vehicles that emit less carbon dioxide such as hybrid vehicles and electric vehicles have become popular. Such vehicles are driven by a battery-powered motor. When such a vehicle travels over a long distance and the state of charge of the battery becomes low, the battery must be charged (refer to Japanese Laid-Open Patent Publication No. 9-161898).
The charging of a battery involves an electrolytic reaction of compounds and ions in battery cells of the battery. This lengthens the charging time. Thus, when a user leaves the vehicle while the battery is being charged, someone may remove the power plug to steal electricity. Hence, power plug locking devices have been developed to prevent unauthorized removal of the power plug from a vehicle.
One type of such a power plug locking device includes a lock cover that uses a lock bar, which is arranged in an power plug inlet of a vehicle, to restrict the movement of a pivotal hook (also referred to as a lock arm), which is arranged on a power plug. In this structure, when the power plug is connected to the inlet, the lock arm is pivoted and hooked to a projection on the inlet. This holds the power plug on the inlet. The lock arm has a basal portion that includes a lever. The lever is pushed to pivot the lock arm in an opening direction and release the lock arm from the projection.
The arrangement of the lock bar above the lock arm in a state in which the lock arm is hooked to the projection of the inlet restricts movement of the lock arm in the opening direction. This locks the power plug to the inlet. In this state, the power plug locking device is in a lock state. When the lock bar is separated from the lock arm, the movement of the lock arm in the opening direction is permitted. This unlocks the power plug. In this state, the power plug locking device is in an unlock state. In the unlock state, the power plug can be removed from the inlet.
When using the power plug locking device, the lock arm may not be properly hooked to the projection of the inlet depending on the circumstance. In such a case, the lock arm would be in an incomplete hooking state. In an incomplete hooking state, the lock arm would be located above a normal position (correct hooking position). As a result, the lock arm would interfere with the movement of the lock bar, and the lock bar would not be able to move to above the lock arm. That is, the lock bar would not be able to move to a normal lock position. Thus, the power plug locking device would not be able to shift to a lock state.
An incomplete hooking state may occur, for example, when the power plug and the inlet are manufactured by different manufacturers. Further, an incomplete hooking state may occur when the power plug is dropped and the lock arm is thereby deformed or when wear of a pivotal shaft of the lock arm obstructs movement of the lock arm in a closing direction. An incomplete hooking state may also occur when foreign matter is caught in the lock arm or when the weight of the power plug (charge cable) lifts and displaces the lock arm in the opening direction.